Everyone's favorite sparkly Internet meme has a long and strangely scientific history – naturalists and scholars have been obsessing over unicorns for over 2000 years. What turned a scientific curiosity of the year 398 BCE into a virgin-loving Christian symbol?

The Early Science of Unicorns

In his terrific book A Natural History of Unicorns, University of Nottingham geographer Chris Lavers includes a translation of the first known written description of a unicorn. It comes from the writings of Ctesius, a Greek physician and historian who wrote a number of scholarly books based on what he gleaned from Persian archives. In roughly 398 BCE, Ctesius writes:

There are in India certain wild asses which are as large as horses, and larger. Their bodies are white, their heads dark red, and their eyes dark blue. They have a horn on the forehead which is about a foot and a half in length. The base of this horn, for some two hands'-breadth above the brow, is pure white; the upper part is sharp and of a vivid crimson; and the remainder, or middle portion, is black. Those who drink out of these horns, made into drinking vessels, are not subject, they say, to convulsions or to the holy disease [epilepsy]. Indeed, they are immune even to poisons…

This is the only way to capture them: when they take their young to pasture, you must surround them with many men and horses. They will not desert their offspring and fights with horns, teeth and heels; and they kill many horses and men. They are themselves brought down by arrows and spears. They cannot be caught alive.

Keep in mind that the educated Greek audience of the 300s BCE would not have considered India a mythical land. The region was poorly understood, but nobody thought it was mythological. It was clearly a political entity, and less than a century after Ctesius wrote about the nation's incredible animals, Alexander began conquering parts of northwest India. By the 200s BCE, there was a Hellenized "Greco-Indian kingdom," and a lively trade between Greece, Egypt and India.

Aristotle and the Roman historian Pliny the Elder also mention unicorns in their descriptions of Indian animals, and the idea that unicorns were fierce, rhinoceros-like animals from India remained popular well into the 200s CE. These accounts were written by the scientists and scholars of their age, at a time when trade between the West and Asia was on the rise. Many people were hungry to learn more about this place beyond the sea where they got their favorite gems, silks, and spices. Perhaps Ctesius' ass, and those of the Greeks and Romans who wrote later about the unicorn, were even based on sightings of actual, one-horned animals that actually existed in southeast Asia, like the rhinoceros.

The unicorn began as the "one horned ass," a supposedly real animal that inhabited a real land, albeit faraway. But with the rise of Christianity in the West, the unicorn began to change.

Medieval Symbolism

The most famous example of unicorns in medieval art comes from the Verteuil Tapestries, which were probably made in the early 1500s. It's a series of seven panels showing a group of hunters capturing and killing a unicorn, who is ultimately resurrected and shown sitting inside a little corral which represents heaven. The tapestries were made during a time when all Christians would have known that the unicorn represented Jesus Christ. How did a one-horned ass from India become the Lord and savior of the West?

It all comes down to a terrible mistranslation. Basically, there are a number of references to unicorns in the Bible – God's strength is compared to the strength of the unicorn, and there are a lot of references to the unicorns horn being a source of misery and release. The problem is, those references aren't actually to unicorns at all. The people who wrote the Bible were not thinking of that Indian animal the Greeks were on about.

As Lavers explains, the original Hebrew text of the Old Testament mentions an animal called a "reem." When scholars tried to translate this word into Greek, they were flummoxed. They had no idea what this "reem" was. They knew it was big, and it had horns, and that it obviously wasn't a goat. (Goats are mentioned elsewhere in the Bible.) So they translated it as "monoceros," meaning "one-horn." Then, when the Greek Bible was translated into Latin, the word became "unicornus." And that word, translated into English, is unicorn.

Early in the 20th century, when scholars cracked the code on ancient cuneiform script, they finally learned what that mysterious reem really was. In these ancient texts, written around the time when the Hebrew Bible was being penned, there are many references to an animal called a rimu. Like the biblical reem, the rimu was enormous, strong, and had horns. That animal was an ox. So all of those references to unicorns in the Bible? Those are actually to an ox. Which, if you read the actual sections of the Bible, makes a lot more sense.

But for nearly 1500 years, Christians believed in the unicorn version of things. The unicorn came to symbolize Christ, its horn the cross, and its tribulations during the hunt were like Christ's tribulations on earth. Interestingly, the idea that unicorns were attracted to virgins comes from a pagan source. A Latin book called the Physiologus, probably written in the second century CE, mentions that a unicorn can only be caught when it lays its head down in a virgin's lap. Christian analysts seized on this idea, suggesting that this was symbolic of how Christ came into the world – with the help of a virgin.

Keeping all of this in mind, it's easy to understand what those 16th-century unicorn tapestries are all about. Though the one tapestry showing the unicorn putting its head in the virgin's lap has been tattered (you can see one strip from it at left), the other tapestries tell the tale. The unicorn is lured to earth with the help of a virgin, and eventually good Christian men capture him and bring him to the kingdom of heaven. Yeah, it's a little weird that the unicorn fights his capture, and that heaven means being changed to a tree inside a corral. But these kinds of confused symbols are what you get when you combine a pagan tradition with the Christian tradition. (Also, as an aside: There are a lot of pagan versions of the unicorn story where the young woman in question does some seriously naughty things with that horn.)

The point is, the unicorn of the Bible is not the same as that one-horned ass that the Greeks were writing about in the 300s B.C.E. They got mixed up somewhere in translation.

The Modern Unicorn

Today, people still like to play the game that Ctesius began 2300 years ago, attempting to figure out whether there is a real animal that inspired his description. Some have suggested he was referencing a rhinoceros, while others have mentioned rare one-horned goats which occasionally turn up in Asia. Maybe Ctesius and his cohort had seen a narwhal horn, and mistaken it for a unicorn horn. Obviously, we'll never know.

Meanwhile, the medieval interpretation of the unicorn as a rare animal associated with female virginity, is still going strong. Rainbow-soaked unicorns adorn all kinds of consumer items aimed at little girls. Fantasy novels about strong young women feature unicorn protagonists. Even the ironic Internet appropriations of the unicorn are used to celebrate powerful, girly innocence – or, occasionally, to make fun of it.

Going beyond the Christian vs. Pagan unicorns, there is still one definition we can all agree on. Any kind of person or animal who appears rare can be described as a unicorn. In that way, our understanding of the unicorn hasn't changed for over 2000 years. It has traveled across continents and gotten lost in translation, but has never disappeared. It is perhaps the most commonly-seen uncommon animal in the history of the world.